A Just Stop Oil protester shouted “Shame on you” at a judge after she was found guilty along with three other campaigners of taking part in a protest which brought traffic in central London to a standstill.

Ben Plumpton, 70, of Charlestown, Hebden Bridge, West Yorkshire, Gregory Sculthorpe, 38, of Doncaster, South Yorkshire, Naomi Goddard, 60, of Hebden Bridge, West Yorkshire, and Kate Bramfitt, 52, of Hexham, Northumberland, were found guilty after a trial at Stratford Magistrates’ Court of wilfully obstructing a highway.

They were among 80 people who took part in the peaceful protest on November 6 last year which went past the Cenotaph in Whitehall towards Parliament Square and caused major disruption.

Queues of traffic built up as they began slow marching in the road for about 25 minutes, taking up two lanes but enabling cyclists to pass by.

They were each given a conditional discharge for nine months, and ordered to pay a £26 victim surcharge and £310 costs – except Bramfitt, whose costs were reduced to £200 after she described herself as “economically inactive” and not receiving benefits.

Bramfitt then shouted at Deputy District Judge Patricia Evans before storming out of court saying: “What you have done is shameful. How do you live with yourself?

“It is shameful, all of you – you are criminalising people who are fight for your futures. Shame on you, judge.”

The court heard that the demonstrators had not informed the police about the protest beforehand and did not co-operate with officers when they were arrested.

The judge said “public safety had to be managed” and the “impact of the protest went quickly from small to significant”.

The protesters sat or laid down after they were arrested and knew their actions would cause disruption, the court was told.

The judge said: “The traffic on this occasion was barely crawling and brought to a standstill while the arrests were effected.”

Buses were delayed and diversions needed, meaning the impact of the protest had “knock-on effects”.

No prior notification of the demonstration was given by JSO, except to state that there was to be a month of protest action taking place during that period of the year.

Another defendant, Lora Johnson, 40, of Reydon, Suffolk, who was tried in her absence, was found not guilty of the same offence.

She took part in a second march on the same day which involved a group of around 25 women who were holding placards referring to mothers and grandmothers.

Her protest lasted about 15 minutes and “was short and of less impact to other road users”, the judge said.

Johnson did not attend court, while the other defendants represented themselves during the two-day hearing.

Earlier, Bramfitt, who is a long-term environmental campaigner, said the protest was part of the “culmination of lots of actions” to try to make a difference.

She said has spoken to her MP and her neighbours about the issue, and mentioned the recent Hurricane Helene in the US.

Describing the legal process as “basically a nightmare” as she is also looking after an elderly father and has two children at university, she told the court: “I’m doing this to help my mental health because I feel that things will change if enough people shout for change and argue against corruption.

“It has taken a massive mental toll. I get frequent migraines from a lack of sleep. I burn out because of the news and stuff.”

She added: “It just messes with your life, basically, and I feel that we should not have been arrested for just walking down the street.”

Plumpton had told the court: “I feel we had to cause a minimal amount of disruption to be effective”, and said when the police spoke to her she felt “we had not caused enough disruption”.

She said she did not resist arrest and told the officer about her concerns for her granddaughter over climate change, about gas companies, and that a dossier had been sent to the Metropolitan Police.

She added: “I accept there was some disruption. I think that disruption was going to be considerably extremely minor in comparison to disruption caused by flooding.”